Usable data rate is 400 Gbps, 4x current top speeds; should allow for supercharged smartphone networks

There are two major determinants of cellular data network speeds. The first is the physical broadcast infrastructure, which takes into account factors such as number of towers, placement, type of spectrum, and amount of spectrum available. The second major determinant is the physical network backbone -- typically fiber cable.

Every signal that goes to or from your smartphone must be transmitted through a fiber backbone. The faster that backbone is, the faster a carrier's services become, regardless of wireless transmission technology.

The "T-Labs" research group of T-Mobile USA's German parent Deutsche Telekom AG (ETR:DTE) made a splash this week, announcing [press release] that it had worked the kinks out of ultra fast fiber optic transmission, which travel at a theoretical data transfer speed of 512 Gbps (or "the simultaneous transmission of 77 music CDs" as T-Labs puts it).

Real world performance isn't far behind. Deutsche Telekom observed real world speeds of 400 Gbps during a 734 km round-trip along a single-optical fiber test channel running between Hanover and the capital city of Berlin.

400 Gbps is a pretty impressive figure, given that the current fastest deployed fiber networks run at around 100 Gbps, with most networks well behind that even. T-Labs plans to bundle together 48 of the single channels into a bundle that will offer a combined throughput of around 18.75 Tbps (18,750,000,000,000 bit/s) (24.6 Tbps, theoretical).

Deutsche Telekom describes the breakthrough in terms that surely would rile the Recording Industry Association of America -- "A collection of 3,696 CDs could thus be transferred over a single optical fiber — a strand thinner than a human hair — at the same time."

The cutting edge research is part of the company's "Optically Supported IP Router Interfaces" (OSIRIS) project.

"I was working in the lab, late one night..." [Image Source: T-Labs]

For the professional network and electrical engineers T-Mobile offers up some juicy techical tidbits:

The Telekom OSIRIS (Optically Supported IP Router Interfaces) research project realized transmission at a speed of 512 Gbit/s (400 Gbit/s usable bit rate) on a 100 GHz wavelength channel over a distance of 734 km, thus demonstrating a spectral sensitivity of 5 bits/s/Hz in the Deutsche Telekom network.
This tremendous transmission performance was reached using innovative transmission technology with two carrier frequencies, two polarization planes, 16-QAM quadrature amplitude modulation and digital offline signal processing for the equalization of fiber influences with soft-FEC forward error correction decoding in the receiver.

The WDM transmission link consisted of a total of 14 standard single-mode fiber sections with dispersion compensation as required for the neighboring conventional 10 Gbit/s channels.

The high optical input powers of the conventional 10 Gbit/s channels and the dispersion compensation in the fiber sections interfere with the innovative transmission technology due to nonlinearities, including self-phase modulation by the higher input power and cross-phase modulation by the adjacent channels. Despite these worst-case conditions, it was possible to demonstrate the transfer of the innovative high-speed signal simultaneously with conventional 10 Gbit/s signals in adjacent channels in an existing system.

So what’s the best part about the new technology? It requires no fiber replacement -- it merely requires new receivers/transmitters. Deutsche Telekom's T-Labs believes that it is read for commercialization, once the technology is incorporated into the terminal equipmentfrom network vendors like Sweden's Ericsson SpA (STO:ERIC B), China's Huawei, France's Alcatel-Lucent (EPA:ALU), and Nokia Siemens (a joint venture between Finland's Nokia Oyj. (HEL:NOK1V) and Germany's Siemens AG (ETR:SIE)).

If the backhaul to the cell tower can now handle 10Mb/s then by swapping out the transceiver the the cell tower can handle 40Mb/s

In terms of people, equipment, community disruption and money, swapping the transceivers is much cheaper than running 3 additional strands of fiber for each existing strand in the infrastructure.

Routers and other support equipment to support the 4x bandwidth change remain the same whether the capacity of the fiber changes or the number of fibers change. The cost difference is solely in the cost of adding the new transceivers vs the cost of adding new fiber runs.

Or possibly swap out a blade in the router chassis. These are not cheap but even at $100K each (making this up) it is still cheaper than pulling new fiber. The smart companies just pull huge bundles of fiber and light up each strand as needed.